I think you may be overplaying the risk in your mind if your idea of mitigation is to quit your stable, high-paying job before you start.
Most of us started this while doing other stuff full-time, and there are big advantages - you are your own backer, you have that paycheck if things go south, and your employment is also the basis for your credit, which can reduce your cost of capital. The less it costs you to borrow, the more easily you can recover from mistakes.
I started out by renting out rooms in my own house. I don't know if I'd recommend it... too easy to get personal, too much drama comes home, etc, but it did get me through some hard times. Later on, I started out my serious efforts in the business by getting a real estate license, which didn't teach me much about investing or management but still helped with understanding a lot of the legalities, definitely made shopping easier, and has helped me connect to a ton of great service providers (also important). Plus, commission, free continuing education, etc. Again, not necessarily the path for everyone, but helpful for me.
Overall, I know it can be intimidating - just keep reading and keep talking to current investors until you find your comfort zone.